1. Field of the Invention
The present invention relates to a print head of an ink-jet printer and a fabrication method thereof, and, more particularly, to a print head of an ink-jet printer, and a fabrication method thereof, having a damping pattern portion formed in a scribe lane area to prevent damage of a head chip from being generated by a wiper or an external impact during printing, and to prevent a short circuit from being generated between a substrate and lead ends of a wiring of a circuit part due to a compression impact and the like occurring during printing and/or when the lead ends are bonded with bonding pads in a main chip area of the head chip.
2. Description of the Related Art
Generally, as shown in FIG. 1, an ink-jet printer has a print head 1 fixed on an ink cartridge 10 to send and receive an electric signal to and from a printer body through a contact pad 36.
The print head 1 includes a head chip 20 having a plurality of ink jetting portions, and a circuit part 30 driving and controlling each of the ink jetting portions. Each of the ink jetting portions is composed of a heater 25 (FIG. 3) and an ink jetting nozzle 24 to generate ink bubbles, and the circuit part 30 is composed of a flexible printed circuit board in which a wiring 34 and/or switching circuits are formed to drive and control each of the ink jetting portions.
The head chip 20 is provided with a silicon substrate 21 having the heaters 25 and bonding pads 26 formed on an upper surface thereof, a chamber plate 37 disposed on the substrate 21 to define ink chambers 29, and a nozzle plate 23 disposed over the ink chambers 29 and having ink jetting nozzles 24. The bonding pads 26 are bonded with lead ends 32 of the wirings 34 of the circuit part 30.
To supply ink from the ink cartridge 10 into each of the ink chambers 29, an ink supplying manifold 22 is formed to penetrate the substrate 21 from a lower surface thereof to an upper surface thereof.
The substrate 21 on which the chamber plate 37 and the nozzle plate 23 are formed is adhered to a substrate-mounting groove 14 of the ink cartridge 10 by adhesives 50.
The operation of the print head 1 constructed as above will be explained below. First, an ink supplied through an ink supplying hole 12 of the ink cartridge 10 moves into the ink chambers 29 defined by the chamber plate 37 and the nozzle plate 23 through the ink supplying manifold 22 from the lower surface of the substrate 21.
After temporarily remaining in the ink chambers 29, the ink is heated in an instant by heat generated by the heaters 25.
As a result, the ink generates explosive bubbles, and thereby a portion of the ink in the ink chambers 29 is jetted outside the print head 1 through the ink jetting nozzles 24 formed over the ink chambers 29 to form an image on paper.
However, such a conventional print head 10 has the structure that the bonding pads 26 formed on the substrate 21 are adhered to corresponding lead ends 32 of the wiring 34 of the circuit part 30 by piezoelectric bonding.
Accordingly, when the lead ends 32, which are usually formed of copper, are piezoelectrically bonded with the bonding pads 26, which are usually formed of aluminum, the lead ends 32 compress and push an insulating layer 39 in a scribe lane area of the head chip 20.
Thus, when the insulating layer 39 in the scribe lane area is pushed by the lead ends 32, it may be damaged by forming compressed traces 46 at a cutting surface 45, as shown in FIG. 5.
In this state, after being fixed on the ink cartridge 10, the print head 1 is operated to carry out printing operations, and the damaged insulating layer 39 in the scribe lane area is more compressed and fatigued with continuous stress caused by wiping and the like, and, as a result, the lead end 32 comes into contact with the grounded silicon substrate 21 to generate a short circuit.
Also, the conventional print head 10 has the bonding pads 26, each having the structure in which a contact plug 28 is connected with a lower metal 27 through a wide via hole 42 formed in an interlayer dielectric layer 41 therebetween, and thereby the contact plug 28 has a wide and flat recess 28a at an upper surface thereof, as shown in FIG. 4.
Therefore, in piezoelectric bonding, one or more lead ends 32 may not be adhered with the corresponding contact plugs 28 of the bonding pads 26 well, so that bonding therebetween is poor.
In this state, when a wiper frequently contacts the poorly adhered lead ends 32 to wipe the print head 1 during a wiping operation, the poorly adhered lead ends 32 may be detached from the corresponding contact plugs 28, causing the corresponding ink jetting portion to not jet ink, thereby resulting in poor printing.
Further, the conventional print head 10 has the structure in that the ink supplying manifold 22 penetrates the substrate 21, so that the substrate 21 of the head chip 20 is mechanically weak. Therefore, even when a small impact is imparted on the substrate 21, the substrate 21 may be cracked centering on the ink supplying manifold 22.
Also, the conventional print head 10 presents a problem in that heat generated in the head chip 20 by the heaters 25 and the like during printing is not radiated outside through the ink cartridge 10, but accumulated in the head chip 20, thereby shortening the life span thereof, or deteriorating the ink jetting efficiency thereof.